EP2185355B1 - Method for producing a security and/or valuable document and document thus obtained - Google Patents

Description

Field of the invention

The invention relates to a method for producing a security and / or value document with at least one security element, wherein the security and / or value document from at least two interconnected by thermal lamination polymer layers is formed, wherein the security element in the course of thermal lamination between adjacent polymer layers or embedded in a polymer layer, and wherein at least one of the polymer layers is formed of a polymer having a glass transition temperature of less than 140 ° C, as well as a security and / or value document produced by such a method.

Prior art and background of the invention

A method of the type mentioned is known from practice. In this case, card-shaped security and / or value documents are produced at low process temperatures, for example using PVC (glass transition temperature T _g = 91 ° C.). This allows the installation or the lamination of security elements between the polymer layers in a simple manner in the course of the lamination process and so in a process-technically simple manner. A disadvantage of the extent known security and / or Value documents are that they are relatively easy to manipulate by delaminating the polymer layers, thus gaining access to the security element. Therefore, such technologies are used in documents whose manipulation does not endanger the document, for example in the case of telephone cards. For the production of, for example, identity documents, such as ID cards, this technology is not suitable because of the risk of manipulation.

It is also known, for example, from DE-A-10013410 To form security and / or value documents with polycarbonate (PC) films, wherein the polymer has a glass transition temperature of typically 149 ° C. There is a lamination of the films or layers at high temperatures and pressures, typically 200 ° C and surface pressures of 300 to 500 N / mm ² . These process conditions ensure intimate bonding of the various layers to a monolithic card body whose integrated security elements are protected against tampering since delamination is virtually impossible. Although some security elements such as RFID chips can be laminated between layers in the course of lamination, one is limited to components (chip, antenna, contacts) which have the thermal stresses without loss of function or functional restriction. But even if the security elements survive the thermal stress during lamination without loss of function or limitation, excessive stress leads to undesirable artificial aging. In addition, in Security and / or value document often further or other security features are integrated, which do not survive the described thermal load without destruction. Therefore, in order to avoid the unacceptable thermal load, it is known to subsequently integrate such security features in the security and / or value document. For this purpose, a cavity is milled for the security element, for example a contact-type chip, in the previously laminated layer composite, and the security element is then adhesively bonded into the layer composite with an adhesive. On the one hand, there is no sufficiently intimate bond between the security element and the layer composite. On the other hand, this technology also requires process steps for installing the security element (milling, gluing, etc.), which is technically complex and expensive.

From practice, the use of other special polymers for the layers or films is known, the glass transition temperature is significantly lower than that of the polycarbonate, whereby the process conditions can be significantly modified, for example, lamination temperatures below 150 ° C, which lamination of temperature-sensitive security elements allowed. The same disadvantages apply as described above for security and / or value document made of PVC layers.

Technical problem of the invention

The invention is therefore based on the technical problem of specifying a method for producing a secure against security against delamination and / or value document, by means of which also temperature-sensitive security elements can be securely integrated by way of lamination.

This problem is solved with the features of claim 1.

Broad features of the invention and preferred embodiments

To solve this technical problem, the invention teaches that the polymer layers are formed of the same or different polymers whose base polymers carry the same or different mutually reactive groups, wherein at a laminating temperature of less than 200 ° C reactive groups of a first polymer layer having reactive groups of a second React polymer layer.

Mehrerleilei achieved with the invention. First, layers of polymers can be used which have a lower glass transition temperature than polycarbonate, which can lower the laminating temperature without jeopardizing the intimate bond of the laminated layers. This is because the various polymer layers can not be readily delaminated due to the reaction of the respective reactive groups. Because there is a reactive coupling between the layers between the layers, as it were a reactive lamination. Secondly, due to the lower lamination temperature, security elements are made possible laminating process, which are relatively temperature-sensitive, without any functional impairment due to the lamination process. As a result, a simplified method for producing tamper-proof security and / or value documents with temperature-sensitive security elements is created. Thirdly, the cost of production is reduced as less energy and time is needed for heating and cooling. Finally, it is advantageous that the security elements used are exposed to only a comparatively low artificial aging due to the reduced thermal load.

In detail, there are various options for further education.

It is preferred if the glass transition temperature of the at least one polymer layer prior to the thermal lamination is less than 120 ° C (or less than 110 ° C or 100 ° C), the glass transition temperature of this polymer layer after thermal lamination by reaction of reactive groups Base polymer of the polymer layer with each other by at least 5 ° C, preferably at least 20 ° C, higher than the glass transition temperature before the thermal lamination. In this case, not only is a reactive coupling of the layers to be laminated together carried out, but rather an increase in the molecular weight and thus in the glass transition temperature takes place by crosslinking of the polymer within the layer and between the layers. This complicates delamination in addition.

Preferably, the lamination temperature is less than 180 ° C, more preferably less than 150 ° C. As a result, comparatively very temperature-sensitive security elements, for example containing organic semiconductors or biological molecules, can be laminated non-destructively in the course of lamination. In general, the lamination temperature is above 70 ° C, usually above 80 ° C, 90 ° C or even 100 ° C.

The number of polymer layers is typically but not necessarily in the range of 2 to 30, preferably in the range of 6 to 10. The layer thicknesses of the polymer layers are typically but not necessarily each independently in the range of 30 to 300 .mu.m, preferably 50 to 200 microns.

In principle, all customary base polymers can be used for the various polymer layers. In this case, successive polymer layers may be formed from the same base polymer or from different base polymers. For example, the polymers of the polymer layers may be identically or differently and independently formed from a base polymer which is selected from the group consisting of PC (polycarbonate, especially bisphenol A polycarbonate), PET (polyethylene glycol terephthalate), PMMA (polymethyl methacrylate), TPU (Thermoplastic Polyurethane elastomers), PE (polyethylene), PP (polypropylene), PI (polyimide or poly-trans-isoprene) and copolymers of such polymers ". It is preferred if at least one of Polymer layers is formed from the base polymer PC. Specifically, for example, a layer sequence can be formed, wherein the successive layers of the basic polymers PC / PET, PC / PMMA, PC / TPU, PC / PE, PC / PP, PC / PI, PET / PC / PET, PMMA / PC / PMMA, TPU / PC / TPU, PE / PC / PE, or PP / PC / PP are formed, and optionally further layers can be connected, which are formed from the same or different base polymers.

The choice of suitable reactive groups is easily possible for the person skilled in polymer chemistry. Exemplary reactive groups are selected from the group consisting of "-CN, -OCN, -NCO, -NC, -SH, -S _x, -Tos, -SCN, -NCS, -H, epoxy (-CHOCH _2), - NH ₂ , -NN ⁺ , -NN-R, -OH, -COOH, -CHO, -COOR, -Hal (-F, -Cl, -Br, -I), -Me-Hal (Me = at least divalent metal , for example Mg), -Si (OR) ₃ , -SiHal ₃ , -CH = CH ₂ , and -COR ", where R can be any reactive or non-reactive group, for example -H, -Hal, Cl-C20 -Alkyl, C3-C20-aryl, C4-C20-Aralkyl, each branched or linear, saturated or unsaturated, optionally substituted, or corresponding heterocycles having one or more identical or different heteroatoms N, O, or S ". Other reactive groups are Of course, these include the reaction partners of the Diels-Alder reaction or a metathesis.

As pairings of reactive groups for the respective polymers or base polymers of the various polymer layers to be laminated, there are, by way of example only and not by way of limitation: NCO / OH, NCO / SH, NCS / OH, NCS / SH, CN / OH, CN / SH, epoxy / COOH, epoxy / OH, epoxy / SH, NH2 / COOH, CHO / OH, CHO / NH2,, alkene / COOH, alkene / OH, alkene / SH, alkene / Hal, alkene / alkadiene (Diels-Alder reaction), alkene / -NN ⁺ or -NN-R (radical polymerization), NN ⁺ or -NN-R / OH, NN ⁺ / Aryl, alkene / -NN ⁺ (coupling to hydrazone), COOH / Tos, Me-Hal / Hal, Si (OR) ₃ / -SiHal ₃ (in various combinations).

Here, a first reactive group of a pair is bonded to a base polymer of a first polymer layer, and the second reactive group of a pair is covalently bonded to a base polymer of a second polymer layer to be bonded to the first polymer layer. Of course, all other combinations of reactive groups known to those skilled in polymer chemistry and not mentioned here are also possible.

In the context of the invention, it is essential that the polymer layers of the invention are structural polymer layers, ie not merely layers for adhesion or adhesive layers. The term of a structural polymer layer means that it has a function which at least supports the mechanical strength of the document. Such structural polymer layers are typically solid per se and at room temperature, have a glass transition temperature of generally more than 90 ° C, and are non-adhesive at 20 ° C. It is equally important that the polymer layers are at least directly contacted and laminated with each other in subregions, ie no adhesion promoter layers are interposed in such subregions.

Of course, a full-surface contact between the polymer layers is possible.

The reactive groups may be attached directly to the base polymer or linked to the base polymer via a spacer group. Suitable spacer groups are all spacer groups known to the person skilled in the art of polymer chemistry. The spacer groups may also be oligomers or polymers which impart elasticity, whereby a risk of breakage of the security and / or valuable document is reduced. Such elasticity-promoting spacer groups are well known to the person skilled in the art and therefore need not be further described here. By way of example only, spacer groups may be mentioned which are selected from the group consisting of "- (CH ₂ ) _n -, - (CH ₂ -CH ₂ -O) _n -, - (SiR ₂ -O) _n -, - (C ₆ H ₄ ) _n -, - (C ₆ H ₁₀ ) _n -, Cl-Cn-alkyl, C 3 -C (n + 3) -aryl, C 4 -C (n + 4) -ArAlkyl, each branched or linear, saturated or unsaturated, optionally substituted, or corresponding heterocycles having one or more, identical or different heteroatoms O, N, or S "with n = 1 to 20, preferably 1 to 10.

Regarding further reactive groups or possibilities of modification, the reference " Ullmann's Encyclopedia of Industrial Chemistry ", Wiley Verlag, electronic edition 2006 , referenced.

At least one security element may have a maximum allowable thermal load of 190 ° C, preferably 150 ° C, most preferably 120 ° C, for a duration from 1 to 600 s. Of course, some or all safety elements may also have a higher maximum allowable thermal load.

The invention also relates to a security and / or value document according to claim 11. It contains at least two polymer layers thermally laminated with one another, the polymer layers being formed from identical or different polymers whose base polymers carry identical or different mutually reactive groups, and wherein the reactive groups different polymer layers are reacted with each other. All comments on the method according to the invention apply analogously and vice versa.

The term "base polymer" refers to a polymer structure which does not bear reactive groups under the lamination conditions used. These may be homopolymers or copolymers. There are also modified polymers compared to said polymers.

As security and / or value documents may be mentioned only as an example: identity cards, passports, ID cards, access control cards, visas, tax stamps, tickets, driver's licenses, motor vehicle papers, banknotes, checks, postage stamps, credit cards, any smart cards and adhesive labels (eg for product security). Such security and / or value documents typically have at least one substrate, one print layer and optionally a transparent cover layer. Substrate and cover layer may in turn consist of a plurality of layers. A substrate is a support structure to which the print layer is applied with information, images, patterns, and the like. Suitable materials for a substrate are all customary materials based on paper and / or (organic) polymers in question.

As safety features, in principle, all customary safety elements come into question, regardless of their temperature sensitivity. Among the temperature-sensitive security features are those containing biological molecules, such as nucleic acids (DNA, RNA), proteins, enzymes, antibodies, etc. Also to be mentioned are security elements with electronic components based on doped inorganic semiconductors, organic semiconductors and conductors, and Display components (OLED, LCD, etc.). Security elements may also contain reactive components that provide protection against document modification. The security elements also include substances that are changed in the course of personalization. Examples of these are laser initiators which respond to irradiation with a laser, for example Nd: YAG lasers.

While above and below substantially the steps of producing a composite of polymer layers are described, it is understood that before and after the usual further customary steps of producing a security and / or Value document. Thus, at least one of the polymer layers may be provided with a print layer prior to lamination. Furthermore, at least part of the various security elements to be introduced can already be integrated into a polymer layer, be it applied or cast in or implanted. Subsequent to the lamination of the polymer layers, the actual security and / or value documents can then be formed in the usual manner by way of replacement or cutting. As a rule, during lamination, the polymer layers form a composite which is several times the size of a security and / or value document so that the majority of security and / or value documents can be obtained from a composite. Subsequently, there is typically a personalization or individualization of the security and / or value document. Before or after the personalization, overlay foils can be laminated on both sides, whereby they are slightly larger than the composite, so that the overlay foils connect to the edges of the security and / or value document.

In the following, the invention will be explained in more detail by way of embodiments that merely represent embodiments.

Example 1: Modification of Polycarbonate (PC)

Is used a film or layer based on bisphenol A polycarbonate, wherein a monomer unit in the Formula I is shown. Here, radicals R 1, R 2, R 3, and R 4 are represented, which are formed by one or more different of the reactive groups indicated in the general part of the description, optionally with a spacer group. It may also be a copolymer which is formed with monomers of the formula I and other conventional monomers. The other monomers may be the same or different from the basic monomer of formula I. The other monomers may in turn carry reactive groups or be free of reactive groups. Of course, instead of the formula I, all other customary monomers may also be modified in an analogous manner with reactive groups.

Example 2: Reactive Lamination

Two adjacent layers to be laminated together are composed of a polymer substance of any commercially available base polymer. The base polymer of the first layer is modified with the reactive group -NCO. The base polymer of the second layer is provided with the reactive group -OH. In the course of lamination, the reactive groups of the two layers react with each other, whereby the two basic polymers of the two layers are covalently linked together via -O- (CO) -NH- bridges. A separation by heating to the laminating temperature or even higher does not lead to a separation of the two layers due to the covalent bonds.

Analogously, the respective reactive groups can be epoxy and -COOH. The bridges are then formed by -CH- (CH 2 OH) -O- (CO) -.

In one variant of this embodiment, one or both layers may each have the different reactive groups. Then not only is a reactive coupling of the different layers with one another taking place, but also the different reactive groups within the one or both layers react with one another with the result that the glass transition temperature of the one or both layers is increased.

In the following Table 1, exemplary base polymers for two to be laminated together Polymer layers with base polymers having respective suitable reactive groups. Here GP stands for base polymer and RG for reactive group. Tab. 1 GP 1 RG 1 GP 1 RG 2 PC NCO PC OH PC NCO / OH PC NCO / OH PC NCO PET OH PC OH PET NCO PC NCO / OH PET NCO / OH PC NCO PMMA OH PC OH PMMA NCO PC NCO / OH PMMA NCO / OH PC NCO TPU OH PC OH TPU NCO PC NCO / OH TPU NCO / OH PC NCO PE OH PC OH PE NCO PC NCO / OH PE NCO / OH PC NCO PP OH PC OH PP NCO PC NCO / OH PP NCO / OH PC NCO PI OH PC OH PI NCO PC NCO / OH PI NCO / OH PC epoxy PC COOH PC Epoxy / COOH PC Epoxy / COOH PC epoxy PET COOH PC COOH PET epoxy PC Epoxy / COOH PET Epoxy / COOH PC epoxy PMMA COOH PC COOH PMMA epoxy PC Epoxy / COOH PMMA Epoxy / COOH PC epoxy TPU COOH PC COOH TPU epoxy PC Epoxy / COOH TPU Epoxy / COOH PC epoxy PE COOH PC COOH PE epoxy PC Epoxy / COOH PE Epoxy / COOH PC epoxy PP COOH PC COOH PP epoxy PC Epoxy / COOH PP Epoxy / COOH PC epoxy PI COOH PC COOH PI epoxy PC Epoxy / COOH PI Epoxy / COOH

In an analogous manner, the further pairings of reactive groups, as mentioned in the general part of the description, can be used. Analogously, composites with more than two of the polymer layers mentioned can also be used with the abovementioned base polymers and the abovementioned reactive groups, with adjacent polymer layers being formed in accordance with the above examples.

Example 3: Production of a layer composite

Are used 6 to 8 layers of film with inventively modified polymers. The individual sheets based on identical or different base polymers are positioned relative to one another by means of edge stop or opto-electronic registration and, for example, connected to one another by means of ultrasonic sonotrodes on a longitudinal side of the sheets. This ensures that the laminate package remains exactly positioned to each other when inserting between two press plates. At least one sheet carries temperature-sensitive security elements. There is a Einzelpaketlamination, for example by means of a rotary table-Heiz-Kühlpressenlaminators. There is one reactive lamination as described above. Such a laminator is particularly suitable for temperature-sensitive security elements, such as biological molecules, better than multi-day heating-cooling transfer presses, since the latter per floor up to 10 press packages are used and the outer press packages are subject to a much higher temperature-time stress than the inner press packages. It is understood that in the case of less or no temperature-sensitive security elements, the multi-day heating-cooling transfer press installation is preferable because of their higher lamination capacity.

Example 4: Production of a composite with increased safety

A further improved security and / or value document is obtained if, as an additional measure, a third polymer layer to be arranged between two polymer layers has holes, recesses, recesses or the like. In the course of lamination, the polymer of the two outer layers penetrates into the holes until the holes are completely filled. Due to the reactive groups, not only does a reactive connection of the two outer layers with the middle layer take place, but rather also the two outer layers are covalently bonded together in the regions of the holes. As a result, the middle layer is additionally bracketed as it were, and delamination is virtually impossible. Only for example be as middle layer called a flexible printed circuit board based on polyimide (PI), which carries, inter alia, an antenna coil. The two outer layers are selected based on a commercially available thermoplastic polymer. The circumference of the outer layers may be larger than the circumference of the middle layer, so that the two outer layers form the edges of the security and / or value document during lamination and completely embed the middle layer.

Claims (12)

1. A method for producing a security and/or value document with at least one security element, wherein the security and/or valuable document is formed from at least two polymer layers connected to each other by thermal lamination,
   wherein the security element is embedded during thermal lamination between adjacent polymer layers or in a polymer layer, and
   wherein at least one of the polymer layers is formed from a polymer having a glass transition temperature of less than 140 °C,
   characterized in
   that the polymer layers are formed of the same or different polymers, the base polymers of which carry identical or different groups being reactive with each other,
   wherein at a lamination temperature of less than 200 °C reactive groups of a first polymer layer react with reactive groups of a second polymer layer and form a covalent bond with each other.
2. The method of claim 1, wherein the glass transition temperature of at least one polymer layer is less than 120 °C prior to thermal lamination, and wherein by reaction of reactive groups of the base polymer of the polymer layer with each other, the glass transition temperature of this polymer layer after thermal lamination is higher by at least 5 °C, preferably at least 20 °C higher than the glass transition temperature prior to thermal lamination.
3. The method according to claim 1 or 2, wherein the laminating temperature is less than 180 °C, preferably less than 150 °C.
4. The method according to any one of claims 1 to 3, wherein the number of polymer layers is in the range from 2 to 30, preferably from 6 to 10, and wherein the layer thicknesses of the polymer layers are each independently in the range from 30 to 300 microns, preferably 50 to 200 microns.
5. The method according to any one of claims 1 to 4, wherein the polymers of the polymer layers are the same or different and are independently formed from a base polymer selected from the group consisting of "PC, PET, PMMA, TPU, PE, PP, PI, and copolymers of such polymers".
6. The method according to claim 5, wherein at least one of the polymer layers is formed from the base polymer PC.
7. The method according to any one of claims 1 to 6, wherein a layer sequence is formed, wherein the successive layers are formed from the base polymers PC/PET, PC/PMMA, PC/TPU, PC/PE, PC/PP, PC/PI, PET/PC/PET, PMMA/PC/PMMA, TPU/PC/TPU, PE/PC/PE or PP/PC/PP, and wherein optionally further layers can be connected, which are formed from identical or different base polymers.
8. The method according to any one of claims 1 to 7, wherein the reactive groups are selected from the group consisting of "-CN, -OCN, -NCO, -NC, - SH, -S_x, -Tos, -SCN, -NCS, -H, epoxy (-CHOCH₂),-NH₂, -NN⁺, -NN-R, -OH,-COOH, -CHO, -COOR, -Hal (-F, -Cl, -Br, -I), -Me-Hal, -Si(OR)₃, -SiHal₃, -CH=CH₂, and -COR", wherein R can be any reactive or nonreactive group such as -H, -Hal, C1-C20 alkyl, C3-C20 aryl, C4-C20 aralkyl, in each case branched or linear, saturated or unsaturated, optionally substituted, or corresponding heterocyclic compounds with one or more identical or different heteroatoms O, N, or S".
9. The method according to any one of claims 1 to 8, wherein the reactive groups are linked via a spacer group to the base polymer, which is for example selected from the group consisting of "-(CH₂)_n-, -(CH₂-CH₂-O)_n-, -(SiR₂-O)n-, -(C₆H₄)_n-, (C₆H₁₀)_n-, C1-Cn alkyl, C3-C(n+3) aryl, C4-C(n+4) aralkyl, in each case branched or linear, saturated or unsaturated, optionally substituted, or corresponding heterocyclic compounds with one or more identical or different heteroatoms O, N, or S", where n = 1 to 20, preferably 1 to 10.
10. The method according to any one of claims 1 to 9, wherein the security element has a maximum admissible thermal load of 190 °C, preferably of 150 °C.
11. A security and/or value document, comprising at least two mutually thermally laminated polymer layers, wherein the polymer layers are formed from identical or different polymers, wherein the base polymers thereof carry identical or different groups being reactive with each other, wherein said reactive groups of different polymer layers are reacted with each other, and wherein the security and/or valuable document comprises a security feature or a plurality of security features having a maximum admissible thermal load of 190 °C.
12. The security and/or valuable document according to claim 11, wherein the maximum admissible thermal load of the security feature is 150 °C.